Marijuana may prevent the onset of Alzheimer’s

by Steve Elliott

Early use of marijuana apparently delays — and might even prevent — the onset of Alzheimer’s disease, according to a leading scientist in the field. But the work of longtime researcher Gary Wenk of Ohio State University has come to a halt, despite the promising results.

“We found out that people who smoked dope in the 1960s were not getting Alzheimer’s,” Wenk explained, reports KJ Hiramoto at the Seattle PI. “These 90-year-olds without dementia were telling us things like, ‘Well, I drank whiskey and smoked dope,’ and these are the things they remember. They don’t remember habits like how often they ate broccoli.”

Maddeningly, Wenk’s research ground to a halt due to political, legal and financial reasons.

“The evidence in animals is clear but making the leap to humans means that you have to find a drug company willing to handle the lawsuits and the money,” Wenk said.

He faced other hurdles, as well. Scientists who wish to research marijuana have to compete for approval and grants from the National Institute on Drug Abuse (NIDA), for which The University of Mississippi is the only source of marijuana. You see, Ole Miss has the only federally legal, grant-funded cannabis garden in the U.S.A.

What makes the situation even worse is that, as admitted even by NIDA Director Nora D. Valkow, M.D., is that the agency is only interested in studying the potential harms of marijuana — not the medicinal benefits.

A spokesperson for the NIDA told the New York Times in 2010 that the agency “does not fund research focused on the potential medical benefits of marijuana.”

“As the National Institute on Drug Abuse, our focus is primarily on the negative consequences of marijuana use,” NIDA spokeswoman Shirley Simson told the Times.

And under federal law, the NIDA must approve all clinical research involving cannabis. It tightly controls which investigators are allowed access to the federal government’s Ole Miss marijuana supply, which is grown (and then stored, for years) at the research facility in Oxford, Mississippi.

Catch-22, anyone?

“I am not funded to do marijuana research,” Wenk said. “It cost me about $100,000 to do a whole experiment, $10,000 just to buy the molecule, and every old rat is $150. You can see how things add up, and individuals can’t afford them.”

British researchers find corroborating evidence

A paper published in the British Journal of Pharmacology suggests that the cannabinoids in marijuana are likely not only to prevent the onset of Alzheimer’s, but also of Parkinson’s disease, Huntington’s disease, and age-related dementia, reports Brandon Isaak at the Marijuana Policy Project.

Chronic brain inflammation, oxidative stress, and intra-cellular dysfunction are the primary reasons people develop these debilitating neurological diseases, and the study found that both THC and CBD, found in marijuana, help protect nerve cell function in users, significant reducing these harmful conditions.

The cannabinoids tap into the endocannabinoid system, reducing inflammation, protecting brain cells from oxidative damage, and promoting cellular health on multiple levels, according to the researchers.

Showing promise: ‘Old people are going to win’

Wenk’s research — before it was halted, anyway — was showing promise to middle-aged and older Americans. Cannabinoids found in marijuana may delay the onset of Alzheimer’s so effectively that people are more likely to die of old age before showing any signs of dementia.

In the study, Wenk dosed rats in his lab at Ohio State a dosage equivalent to one puff of marijuana every day. In old rats that had impaired memory due to brain inflammation, that single puff a day was making them smarter. Not only were they more intelligent, but some of the pathological changes in the rats’ brains — due to aging — were being reversed.

“Essentially, what we found was that we know that as people get older, their neurogenesis drops to zero,” Wenk said, referring to the process through which new brain cells are created. “And that’s part of the reason old people have a problem with their memory and depression. What we found was that not only did the single puff a day reverse the memory impairment but also restarted neurogenesis.”

According to Wenk, delaying the end of neurogenesis (which means the regeneration of neurons) helps middle-aged Americans and their families in a very easy-to-measure way: in their pocketbooks.

“If we can keep a person out of a nursing home for five years, we’ve saved that family and their insurance companies an awful lot of money,” Wenk said. “No matter how we spin this, old people are going to win.”

“I’m incredibly excited about it, because this is the first time we’ve ever had a compound that actually works in the old brain,” Wenk said. “Everything works in the young brain, but this is working in old brains. So this means if you’re, 60, 70, and you’re having problems with mental decline? We might have a mechanism that could target that.”

"Very low doses are effective," Wenk said — even just one puff of marijuana a day helps, according to his research. "This is just the beginning of what we believe we’ll uncover as we investigate this line of research,” he said.

Blocking endocannabinoids may trigger early Alzheimer’s

Another study from a team of investigators at the Stanford University School of Medicine led by Daniel Madison has implicated the blocking of endocannabinoids — the brain’s own internal versions of the active compounds in cannabis — in the early pathology of Alzheimer’s.

It seems a substance called A-beta, suspected to play a key role in Alzheimer’s because it’s the main part of clumps which dot the brains of Alzheimer’s patients, may, in the early stages of the disease, impair learning and memory by blocking the beneficial action of endocannabinoids.

The group at Stanford is now trying to suss out the molecular details of how this occurs. Pinning down the details could pave the path to new ways to stave off the learning disabilities and memory deficits that characterize Alzheimer’s — and could also help explain how smoking marijuana helps to delay or even prevent its onset.

In the study, published in the June 28, 2014 issue of the scientific journal Neuron, the researchers detail how pyramidal cells in the brain underpin learning and memory. This assures, they learned, that high-intensity input such as falling down or burning your finger tends to stick in your memory, thus presumably help avoid such mishaps in the future.

Pyramidal cells are encouraged to ignore “noise” signals — they constantly receive random signals from upstream nerve cells — by a sort of “wet blanket” nerve cells called interneurons. These secret an inhibitory substance, the molecular equivalent of an indifferent shrug or yawn, signaling that the input is not really very important.

But when the news actually is significant, pyramidal cells secrete their own “Now just you wait a minute, this is important!” chemicals. And guess what? Those chemicals which signal the importance of incoming information are none other than the endocannabinoids.

Madison speculates that when we smoke marijuana, the phytocannabinoids from the plant have the effect of enhancing the perceived “importance” of events that happen while we’re under the influence of pot.

And another likely effect is inhibiting the “wet blanket” effect of interneurons — which, in Alzheimer’s, needs reducing to increase the ability to learn and remember.

Increasing tolerance

The federal Schedule I illegality of marijuana, under which it is officially considered to have no medical uses and a high danger of abuse, has stymied Wenk’s research. But the scientist has noticed a refreshing trend — a major shift in the cultural tolerance of cannabis, particularly from young people, including his students.

“I have really seen a shift in 10 years of increased marijuana tolerance,” Wenk said. “In my class, people are more than willing to discuss their marijuana use. But they would be embarrassed to mention that they smoke cigarettes.”

With Alzheimer’s ranking as the sixth leading cause of death in the United States — and with more than five million Americans currently struggling with the disease, which has no known cure — you’d think that lab results as promising as Wenk’s would have attracted major funding by now. But that’s not the case, because, as we’ve pointed out, the NIDA isn’t really interested in knowing about the medical benefits of marijuana — just its dangers.

Wenk, who has researched the effects of Alzheimer’s on animals for about 40 years, has shared his findings in his book, Your Brain On Food.

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